Pathankot (Punjab): Occasional sound of firing could be heard from inside as search and combing operations by security forces continued at the Indian Air Force (IAF) base here today, nearly 55 hours after terrorists launched an attack on the frontline facility in Punjab.

Police sources stationed at the air base said that the firing could be linked to the mopping operation as security forces were trying to secure the area. Firing could be heard during last night and today also.

The terrorist attack had started at 3.30 am on Saturday. "Combings operation continued (on Sunday). This operation is at the completion stage. The operation will continue till the whole air base has been cleared of any intruders," Air Commodore JS Dhamoon, the Air Officer Commanding (AOC) of the Pathankot Air Force Station told the media.

NSG and army commandos conducted a thorough mopping of the entire area where the terrorists, suspected to be from Pakistan, had been cornered, police said. IAF helicopters flew through the night over the air base to assist ground forces in the counter offensive against the terrorists.

"Army and para-military forces have surrounded the entire air force base, which is spread in a huge area and has undulating terrain, buildings and forest area which has to be searched very carefully to avoid casualties. That it why the operation is taking longer time to complete," a Punjab Police officer said, adding that steps were being taken to ensure that no terrorist is able to escape from the area.